Tin plate



March 20;, 1928. 1,663,445

S. A. DAVIS TINPLATE Original Filed June 25. 1919 s Sheets-Sheet 1 3 N Ag )Vz'hzesses:

arch 20, 1928.

S. A. DAVIS TIN PLATE 3 Sheets-Sheet 2.

Origglnzil Filed June 25. 1919' March 20, 1928. 1,663,445

s. A. DAVIS TIN PLATE Original Filed June 25. 1919 3 Sheets-Sheet 5fnvenhr:

Patented Mar. 20, 1928.

UNITED STATES PATENT OFFICE.

STEWART A. DAVIS, OF PITTSBURGH, PENNSYLVANIA, .ASSIGNOR T AMERICA-NSHEET ANDTIN PLATE COMPANY, OF PITTSBURGH, PENNSYLVANIA, A CORPORA- TIONOF NEW JERSEY.

Original application filed June 25, 1919, Serial No. 306,521.

January 8, 1925.

This invention relates to tin plate, and

I more particularly to that cheaper grade of t n plate having arelatively thin or light weight coating of tin known commercially ascoke plate, this application being a division of my copendingapplication, Serial No. 306,521, filed June 25, 1919, for manufacture oftin plate, issued March 3, 1925, as Patent No. 1,528,407.

Tin plate is sold universally by the base box, a base box being theequivalent of 112 plates, ll inches by 20 inches by 30 gage, or totaling31,360 square inches superficial area.

The standard commercial grade of coke plate as heretofore made carriesapproximately one and one-half pounds of tin per base box, is without ahigh luster,and is dull or dry in appearance. The coating on commercialcoke plate is not entirely continuous, but contains small openings orchannels running through the coating to the ferrous sheet underneath andfoiuning what is'technically known as pin holes. As the'thic'kness ofthe coating isincreased on commercial coke plate its luster is improved,approximately in proportion as the weight of the tin per base boxincreases. The number of pin holes,

however, do not decrease in the same proportion, in fact the number ofmains about the same.

In the manufacture of tin plate as carried on commercially with thetinning machines pin holes re- TIN PLATEP Divided and this applicationfiled Serial No. 1,303.

crushed and flattened against the iron base,

of the prior art, the cleaned iron or steelplate or base is passed'byhand, through a layer of flux into a bath of molten tin pass ing throughthe bath and surplus adhering tin removed from its surfaces by means ofrotary. spring pressed sets of feed out rollers. When the ferrous baseand molten tin are firstbrought into contact, a layer of iron-tin alloyforms on the surfaces of the base, this alloy having a melting pointhigher than that of the molten tin itself. The result of this action isthat fine needlelike crystals of iron-tin alloy are formed, whichprotrude from the surfaces of the iron base and form a fine spongy orporous network of crystals, the interstices of which are filled withmolten tin. When the iron base with its adherent alloy layerof crystalsis later'passed between the feel-out rollers of the tin pot, which arelocated within a.

and a large portion of the molten, interstitial tin is squeezed out andflows oif the plate. The plate, as it emerges from between the exitrollers, comprises a ferrous base covered with a coating composed of themixture of crystals of iron-tin alloy and pure tin. The presence of thecrystals produces what can be seen under a microscope to be a roughirregular surface, which in turn imparts the dull, or as technicallytermed, the dry appearance to the surfaces of coke plate as heretoforeproduced. In carrying out this old process, great care 13 taken to keepthe yield at or below a certain limit, the yield Varying with differentgrades of tin plate and being determined by the particular grade of tinplate being ma de.- Experience has shown that in practicing this oldprocess the yield increased with an increase in the speed at which theplates pass through the tinning bath, and it has been the belief that aspeed of 100 to 120 nches per minute was the maximum possible in themanufacture of coke plate. It is also a matter of general knowledge thatkeeping the plates within the bath of molten tin for too long timeinterval results in making plates having black spots (i. e. spots wherethe tin does not adhere to the base).

Referring now to the drawings which yention Figure 1 is a plan showing atinning pot adapted to produce tin plate according to this invention.

Figure 2 is a longitudinal section, ori'the line IIII of Figure 1.

Figure 3 is a sectional end'elevation, on the line IIIIII of Figure 2.

Figure 4 is a plan, and Figure 5 is a side elevation, showing details inthe construction of the roller driving mechanism for the machine.

In the accompanying drawings, the letter v A designates-a tinning pot,in itself an old and approved form. The pot is separated transversely bya vertical wall or artition 2 into compartments B and O; T e lower edgeoffth s partition 2, which terminates above the bottom of the tinningpot and the upper edge of a rib or projection 3 on the bottom of the potdefine the width or vertical dimension of a narrow passage or openpurerthan the other after the apparatus has been put into operation. Theparticularpot'shown is of a width which permits of two or more lates,side by side, being passed through t e tinning pot. (See Figures 1 andAny of several known means may be used for heating the tinning pot and,preferably, will be constructed and ar ranged to maintain the tin in thecompartment B at a considerably higher temperature than the tin in thecompartment C.

The pot heating apparatus, not forming part of this invention, is notshown nor further described.

- The side walls of the compartment G at the exit end of the pot areextended upwardl so that this compartment is considera 1y deeper thanthe compartment B, this old and well known construction making itossible to maintain abody of oil, general y palm oil, of the requisitedepth or thickness, on top of the molten tin in the compartment 0. Thelevels at which the bath of molten tin is maintained in the pot areindicated by the line X-X of Figure 2, and a thin layer H'of flux ismaintained on top ofthe tin in the compartment B on the entrance end ofthe pot. The approximate level of the upper surface of the oil isindicated by the line YY in Figures 2 and 6. Due to the weight of thebody of oil on the tin in-the compartment C, the level of the tin inthis compartment is somewhat lower than that of the molten bath in thecompartment B.

Located immediately above the upper edge ofthe com artment B, at theplate entering side of t of spring pressed feed rollers E and F, whichare arranged to move the pickled and washed plates forwardly anddownwardly into the tin pot at an angle to the horizonta The set of feedrollers E is composed of rollers t and 5, and the set of rollers F whichis composed of rollers 6 and 7 are at p a somewhat lower level than theset E. An adjustable deflecting roller G is located belowand on thedischarge side of the set of rollers F, to guide and direct the frontend of the plates forwardly and downwardly e tinning pot, are two "setsp through the layer H of flux into the molten tin in the compartment B.

Positioned within the compartment B, closely adjacent to the passage D,is a set of pressure rollers I composed of rollers 8 and 9. The upperroller 9 is mounted in sliding bearing blocks 10 which are provided withupwardly extending tension rods 11 which extend through a transverse bar12 and through the overhang portion 13 of a bracket member 14 mounted onthe bar 12. The center of the roller is provided with a hearing surface15, and a bearing shoe 16 is mounted over-the'upper portion thereof. Theshoe 16 is also provided with a rod 11 which is mounted as describedabove. The rods 11 are each provided with a shoulder 17, and a coilspring 18 is mounted around each of the rods 11 above the-shoulder 17 sothat one end of the spring bears against the shoulder 17 and the otherend bears against the overhang portion 13 of the bracket 14. The sprin s18 serve to normally hold the roller 9 1n resiliently closed contactwith the roller 8.

The roller 8 is mounted in bearing blocks 19 and is provided with acenter bearing .portion 20 which is supported by a bearing shoe 21mounted on a post 22 which is pivotally supported at its lower end on abar 23 which is mounted for rocking movement in the frame 0 and has itsend pivotally connected to a link 24. The link 24-. has its upper endpassed through a bracket 25 on the frame 0 and is provided with ashoulder 26 at a point below the bracket 25 adapted to support the lowerend of a coil spring 27 which is mounted around the link and has itsupper end bearing against the bracket 25. The bearing shoe 21 and itsresilient mounting described above, serve to normally force the roller 8toward the roller 9 and to prevent bowing of the roller at its center.

The pressure rollers 8 and 9 which are submerged in the molten tin inthe compartment B, have the doublefunction of low feeding the platesfrom the vcompartment B It should be noted that the sets of feed-inrollers E and F and the guide roller G are above the layer of fiux H,and that thesuccessive plates are mechanically fed 'and guided into thetinning pot. This mechanical feed is important since it permits thelates to be fed through the flux at the same speedthat they are fedthrough the tin, while in the old hand-feed pots the plates are passedthrough the flux at a high speed and through the tin at a relatively lowspeed. g

The location ofthe pressure rollers I with respect to the layer of fluxH also should be noted. It has heretofore been considered impossible touse submerged rollers in a tinning machine.

I have discovered, however, that by positioning the rollers I so thatthe distance from the flux'H is not too great, and by allowing theplates to remain in the flux a sufiicient time, that suflicient flux iscarried down by the plates to maintain the rollers I in workingcondition. ,In other words, I have discovered that suflicient flux mustbe supplied to the rollers submerged in the tin to'keep them in workingcondition and that the first rollers coming in contact with the surfacesof the plates after they pass through the flux utilize substantially allthe flux carried by the plates. Therefore, to produce plates free fromblack spots it is the better practice to have only one set of rollerssubmerged in the tin, and these rollers should be suificiently close-tothe flux to receive a plentiful supplyof the flux carried to them On thesurfaces of the plates.

Two sets of feed-out rollers J and K are provided which are locatedwithin the body of oil maintained on top of the tin in the compartment Cof the pot A. The sets of rollers J and K are composed of rollers 30, 31and 32, 33, respectively, which are arranged to not only feed the platesout of the tin pot, but also act to" squeeze ofi surplus tin from thesmooth alloy, coated surfaces of the plates passing upwardly out of thetin ning pot; The body of oil in which these rollers are submerged actsto prevent the molten coating on the surfaces of the plates fromcontacting with the atmosphere, until after the excess coating has beenremoved therefrom.

An inclined apron 34 is provided at the entrance end of the compartmentB of the pot to receivethe plates as they are delivered to the tinningpot. Plates 35 and 36 form a guide L for directing the. front end of thesuccessive plates as they emerge from between the set of rollers E intothe bite of the set F.

Curved guide plates 37 and 38 forming a guide M are positioned withinthe compartment B so as to direct the forward end of the plates beingtinned into the nip of the set of pressure rollers I, as is clearlyshown in Figure 2. These guide plates-37 and 38 are, preferably, ofskeleton form so as not to interfere with the settling of scruff and.dross or any other foreign material in the molten tin to the bottom ofthe compartment- B of the pot.

Curved guide plates 39 and 40 form a guide N which directs the forwardend of the plates emerging from the set of pressure rollers I upwardlyinto the bite of the lower set J of two sets of feed-out rollers J androtate these rollers.

The framework 0, which supports the sets of feed rollers E, and F, guideroller G and pressure rollers I, and the stationary guides L and M, isremovably secured within the compartment B so as to permit the feed-inapparatus to be removed bodily from the pot whilethe tin bath ismolten." This is done at intervals in order to clean the tinning pot,and when necessary to make repairs to the feed-in apparatus. The sets offeed-out rollers J and K and guide N are similarly mounted on aframework P in the compartment C of the pot, and are taken out of andreplaced in the compartment Gin the same manner as the apparatus withinthe other compartmentB.

The feed rollers-4 and 5 of the set E are connected together by a pairof spur gears 42 to positively drive both of these rollers, and therollers 6 and 7 of the set F are likewise connected by spur gears 43 fora similar purpose. -The pressure rollers 8 and 9 are also connected'byspur gears 44 to positively The pair of feed-out rollers J comprisingthe rollers 30, 31 are connected by spurgears 45 to positivelyrotateeach roller, and the feed-out rollers K comprisim the and 33 aresimilarly connected 46 for the same purpose. I

The rollers 4 and 6 of the feed-in rollers and roller 8 of the pressurerollers are the driven members of'their respective sets.

The feed roller 4 is provided with a spur gear 47 which is in mesh witha spur gear 48 on a stub shaft 49, the stub shaft being journaled in theframe 0, and carrying a sprocket wheel 50 which is adapted to be drivenby a chain from a suitable motor, (not shown A drive shaft 51 isjournaled in suitable earings 52 on an angle support 53 which isfastened on one side of theframe 0. Each of the rollers 4 and 6 androller 8 are provided with bevel gears 54 which mesh with bevel gears 55on the shaft 51. From by spur gears the above it will be clear that allof the rollers 4, 5, 6, 7, 8 and 9 are driven from the I, and feed-outrollers J and K, are arranged rollers 32' this wheel being mount-- sothat each of the rollers will be positively driven, at a uniform surfacespeed of at least 150 or more inches per minute, thereby providing forfeeding plates into, through,

- ing and eirpel surplus tin from the interstices v plates to pressure'ing to the plates as of the porous coating, then passing the platesthrough a second bath of substantially pure tin, and then removing theplates from said second molten .tin bath through a body of oil, andsubjecting the coated to remove excess tin adherthey pass through theoil, and maintaining the travel of said plates at a uniform speed of atleast 120 inches per minute from the time they enter the flux until theypass out of the oil bath on top, of the tin bath. y

In carrying out the improved method of this application with a machineconstructed as above described, the uneoated ferrous metal plate afterbeing pickled and washed, is placed on the apron 34 and moved downwardlyuntil its front end enters'the nip of the set of feed rollers E. Theplate, upon entering these rollers, is then mechanically fed forwardthrough the nip of the second pair ot feed rollers F, which are locatedimmediately above the layer of'fiux H in the flux box. In passing frombetween the rollers F the plate, is directed into the flux H by theadjustable guide roller G so that it does not come into contact with anystationary part of the apparatus below the level of the flux, thusavoiding dislodgment of congealed flux and other substances which havepreviously been deposited and which otherwise would be carried into themolten tin bath. The uniform movement of the sheet through the flux intothe tin bath and between the pressure rollers I carries sufficient fluxto these submerged rollers to maintain them in proper working condition.IIeretofore in the well known hand-feed apparatus the plates were fed ofthe successive steps of uide L into the After pasing through the flux,the plate enters the molten tin in the compartment B, passing throughthe curved guide M. This guide is preferably of skeleton construction asshown, so as to pern'iit deposition on the bottom of the compartment Bof scruff,

dross or other foreign matter. The guide M discharges the plate into thenip of the set of pressure rollers I.

As the. plate is passed through the tin in the compartment 15 aniron-tin alloy coating is formed on the surfaces. thereof, and as theplate passes between the pressure rollers I the alloy 'is flattened andsurplus tin is squeezed out and removed from the alloy coating. Theplate then passes through the opening D and is deflected by the curvedguide N upwardly through the bath of tin in the compartment C and intothe nip of the first pair of feed-out rollers J which are in the oilbath above the tin in the compartment C.

As the plate passes through the feedout rollers J and K, any excess tinadhering to the iron-tin alloy on the plates is removed by the pressureof these feed rollers, and a finished coke plate is produced having anouter layer of substantially pure tin which has the luster and otherproperties and characteristics of the heavy coating of charcoal platestogether with the desired light yield.

The advantages of my invention, which will be apparent to those skilledin the art, are in the production of a coke plate having the finish orluster of the more heavily coated charcoal plates, but with a lightercoating of tin than has been possible heretofore.

I claim- As a new article. of manufacture a coke plate consisting of aferrous metal base coated with tin,'and having the thin light weightcoating of from 1.5 to 2.5 pounds per base box characteristic of cokeplate and bein (Y substantially continuous, non-porous and free from pinholes, providing a bright luster typical of charcoal plate.

In testimony whereof I have my hand. V

STEWART A. DAVIS.

hereunto set

